The long term objectives of this study are to understand the mechanical and reflex effects by which the airway and airway neuroreceptors modify breathing and to appreciate the significance of these effects in control of breathing in man. The rationale is that the status of the airway and airway neuroreceptors can alter minute ventilation (V/E) and breathing pattern in normal subjects and those with airway diseases. The proposal will focus on effects of airway anesthesia on breathing in man. In particular it will focus on one known effect, the increase in V/E that occurs during C02 inhalation after airway anesthesia. The specific aims of the proposal are: 1) to determine if the increase in V/E is related to an increase in neuromuscular output to breathe or to a decrease in mechanical load on breathing, 2) to establish if the increase in V/E requires anesthesia of the oropharynx or anesthesia of the larynx and lower airways, and; 3) to determine if there is an effect of airway anesthesia on quiet breathing or C02 stimulated breathing during sleep. Each study will include airway anesthesia achieved by inhaling aerosolized lidocaine. Measurements will be made of V/E, breathing pattern, mouth occlusion pressure (P100), and mechanics of the respiratory system before and after airway anesthesia in normal subjects. In the course of each study large inter- and intrasubject variability may be encountered in the breathing of subjects. These problems will require extensive experimental controls and a powerful statistical approach - multifactorial analysis of variance on repeated measurements in the same subjects. In this way small changes in each variable can be identified after airway anesthesia. These changes can then be related to the increase in V/E inferring a mechanism for the effect of airway anesthesia and presumed inhibition of airway neuroreceptors on C02 stimulated V/E.